It is well known to use gas flow regulators in conjunction with supply sources of gases such as tanks of oxygen containing high pressure oxygen or oxygen gas mixtures, to control both the pressure and the rate of flow of the oxygen or oxygen mixture being released from the tank. More recently, there have been developed separate oxygen control devices that conserve the oxygen supply by limiting its release only during useful times, as for example, only during the inhalation period of the breathing cycle of a patient using the oxygen. Such devices are sensitive to drops in pressure caused by inhalation to activate the oxygen flow only during inhalation. To control the xe2x80x9ceffectivexe2x80x9d rate flow of the oxygen, but without adjusting the regulator, the oxygen in such devices may be supplied at one flow rate but a breath cycle counter employed to selectively activate the flow only at intermittent breathing cycles, for example after each second, third or fourth cycle.
It also is known that only the air or oxygen inhaled at the initial or effective stage of inhalation or inspiration, is that which is usefully absorbed by the lungs. The remaining inhaled air or oxygen in the latter stage of inhalation is usually exhaled before it can be absorbed by the lungs. To take advantage of this phenomenon, there are devices that conserve oxygen supplies even more by actuating the flow of gas upon initial inhalation but also terminating the flow of oxygen after the effective stage, say 190 ms after initial inhalation. With such devices, it is known to increase or decrease the effective flow rate of the oxygen by increasing or decreasing the activation time during each inhalation cycle.
As all of the above features are either necessary or desirable and useful, we have invented a new combined oxygen regulator and conservation device that is flexible in its use, compact in size, simple and convenient to set and operate in its modes of operation, and further can increase the mobility of users of the oxygen supply.
The present invention comprises a combination regulator and conservation device that conveniently can be positioned directly on an oxygen tank containing oxygen or an oxygen mixture in gas or liquid form, or the wall outlet of a master oxygen system, for connection directly to the tank or outlet, thereby eliminating the need for a separate hose between the regulator and the conservation device. Contained within the device in a compact package is an oxygen regulator, a power supply or external power supply connection, and a control circuit to control the effective dose of oxygen by control of the interval(s) and time(s) of the oxygen flow. Further according to our invention, the device can be selectively controlled to provide either an intermittent pulse of oxygen to be supplied on every inhalation stage cycle at variable times during the inhalation stage, or an intermittent oxygen supply mode delivering a predetermined amount of oxygen but only during selectable alternating inhalation cycles, or an override mode for a continuous supply of oxygen.